fix: always reference the correct ServiceAccount and Secret namespace (#11)

### Description of the change

Use the same namespace template for all `namespace:` fields, this would be no error if the ServiceAccount would had the same different template than the reference.

I found this while analyzing existing code statically via `namespace:` search.

Updated to also use correct namespace in existing secret lookup

### Benefits

Previously if .Values.namespace and .Release.Namespace didn't match this might caused an install error.

e.g. in values.yml
```yaml
namespace: test
# ** enable provisioning job is required
```
However installed using
```
helm install -f values.yml --create-namespace --namespace install-name-space myactions .
```

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-actions/pulls/11
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Christopher Homberger <christopher.homberger@web.de>
Co-committed-by: Christopher Homberger <christopher.homberger@web.de>

templates/rolebinding-job.yaml

@@ -17,6 +17,6 @@ roleRef:
 subjects:
   - kind: ServiceAccount
     name: {{ $name }}
-    namespace: {{ .Release.Namespace }}
+    namespace: {{ .Values.namespace | default .Release.Namespace }}
 {{- end }}
 {{- end }}

templates/secret-token.yaml

@@ -11,7 +11,7 @@ metadata:
   labels:
     {{- include "gitea.actions.labels" . | nindent 4 }}
     app.kubernetes.io/component: token-job
-{{ $secret := (lookup "v1" "Secret" .Release.Namespace $secretName) -}}
+{{ $secret := (lookup "v1" "Secret" (.Values.namespace | default .Release.Namespace) $secretName) -}}
 {{ if $secret -}}
 data:
   token: {{ (b64dec (index $secret.data "token")) | b64enc }}